As reported to the FAA. Reports are unverified, and codes are left as the FAA publishes them.
What was found
SFO - FLT 11 - EN ROUTE SFO-JFK - FIRE WARNING INDICATION LIGHT ILLUMINATED FOR AFT LAVATORY. RETURNED SFO AND LANDED WITHOUT FURTHER INCIDENT. INSPECTED LAVATORY WIRING, PLUMBING, AND COMPONENTS. RAN BOTH ENGINES AND PACKS. NO FAULTS NOTED. SYSTEM GROUND CHECKED NORMAL OPERATION. (M)